Patent GB-501097-A (GB)
Title: Machine for cutting bevel gears
IPC: B23F5/12
Filed: 1938-03-05
Abstract: 501,097. Gear-cutting. FAES. (:.. and HARBECK, M. and STIFFEN, H. W., (trading as HEIDENREICH & HARBECK). March 5, 1938, No. 6998. [Class 83 (iii)] In a machine for sloping, milling, or grinding the teeth of bevel gears, the rolling generating movement is imparted to the tool or tools and to the work respectively by means of separate rolling cylinders operated by slides connected by a double-armed lever. As applied to a shaping-machine the tool or tools tare reciprocated through the teeth of the blank g and have also a depth feed in the direction of arrow b, Fig. 1. The tools also have a rolling generating movement round the axis of the basic crown wheel while the blank is rotated in unison about its axis. A motor M, Fig. 7, drives through pick-off gears 1, 2, bevel gearing 5, and spur gears 6 an eccentric pin 8 which oscillates a shaft 11 carrying a lever 12 in which the tool slides are pivoted. A second motor M<1> which controls the feed and generating motions drives a shaft 15 which may be braked at 16 when the motor is switched off and drives a lubricating pump through gears 18. The shaft 15 drives, through change gears and worm gears 24, a shaft 25 carrying roughing and finishing feed cams 26, 27 respectively either of which may coact with a roller on a lever 29, adjustably pivoted at 31 and connected to the tool-head to effect variable feed and withdrawal movements of the tools. The tool-head may also be moved for complete withdrawal by a hand lever 33. The worm wheel 24 carries a pin which oscillates a slide 35 connected by segmental bevel gearing and shaft 39<1> to a lever arm which reciprocates a slide 42 connected by one or more flexible bands 43<1>, 43<2> to a cylinder 43. The latter is connected through bevel gearing 45 and belt gearing 47, 4R to the work spindle 49 to impart generating movement thereto. A lever 62, adjustably pivoted at 65 connects the slide 42 to a second slide 63 which reciprocates a carriage 64 connected by a number of flexible bands 66<1> ... 66<4> to a cylinder 66 to impart corresponding rolling movement to the tool head. The rolling cylinders may be of solid or hollow construction or may he replaced hy segments secured to suitable carriers. The proportions L<1>, L<2>, of the lever may be altered in order to secure correct relative rolling movements for cutting different gears without changing the rolling cylinders. The wheel 48 carries a lever 51. Fig. 10, pivoted at 50 and carrying a dog 52 coacting with notches in an index plate 53 secured to the work-spindle to transmit the rolling movement to the work. At a predetermined point in the anticlockwise movement, Fig. 10, a pawl 55 on the lever engages the inclined face of a fixed catch 58 and rocks the lever about its pivot against a spring 54 to disengage the dog 52. At the same time a fixed detent 59 is engaged with a ratchet wheel 60 to prevent movement of the work spindle. Continued movement of the wheel 58 frees the pawl 55, thus allowing the dog 52 to drop into the next notch to index the work and causing the lever to disengage the detent 59. At each rotation of the cam shaft 25 a cam thereon operates a plunger 68, Fig. 12, to operate a ratchet wheel 70 which is held against reverse movement by a detent 72. This movement is transmitted to a wheel connected through a clutch to a sleeve carrying a graduated disc which is set according to the number of teeth to bo cut. The sleeve carries a projection 80 and pin 81 and when the last tooth is cut the pin 81 lifts a lever 82 and disengages the detent 72. The wheel 70 is then returned by a spring to its initial position. During this movement a lever 86 is rocked about its axis 89 to disengage the contacts 86<1> and stop the machine.